Railway-traffic-controlling system



Feb. 10, 1931. s. N. WIGHT RAILWAY TRAFFIC CONTROLLING SYSTEM Filed May16, 192'? 2 Sheets-Sheet l Feb. 10, 1931. s. N. WIGHT RAILWAY TRAFFICCONTROLLING SYSTEM Filed May 16, 1927 2 Sheets-Sheet 2 INVENTOfi/ ,3 BY4 ATTORNEY Patented .Feb. 10, 1931 UNITED STATES" PATENT. OFFICESEDGWICK N. WIGHT, OF ROCHESTER, NEW-YORK, ASSIGNOR TO GENERAL RAILWAYSIGNAL COMPANY, OF ROCHESTER, NEW YORK RAILWAY-TRAFFIC-CONTROLLINGSYSTEM Application filed May 16,

This invention relates to a single track railway signaling system of theabsolute-permissive-block type, and more particularly to apparatus andcircuits for controlling the usual stick relay of such system when colorlight signals are used. 7 a a In an absolute-permissive-block signalsystem, such as disclosed for example, in my prior Patent No. 1,294,736,of February 18, 1919, the desired control of the block signals involvesthe use of a line or signal relay controlled by the track relays of twoadjacent track circuits. Track relays in the usual normally closeddirect current track circuits are 1.1 very slow dropping. This slowdropping characteristic is largely due, it is believed to the fact thatsuch relays are dropped by being shunted by the passing train, and suchshunt-, ing of their windings cause their windings to an act likebucking coils and causes them to oppose a change in the flux in theirmagnetic circuits. These same track relays, on the other hand, arerather quick in picking up when their respective track circuits are 2-cleared, because there is then no short CH: cuited coil opposing a chane in the fla r oi the magnetic circuit thereoi From this t readilyappears that if a line or home relay isjointly controlled through frontcontacts of the relay of two successive track circuits, the passage of ashort train, such as an engine and tender running alone, from onesection thereof into the next section may possibly cause thede-energized track relay to pick up 33 before the energized track relaydrops, so that the line or home relay controlled by these track relaysis momentarily picked up While such train moves from one track circuitupon the adjoining'track circuit. In an absolutepermissive-block signalsystem, as disclosed in detail in my prior patent above mentioned, adirectional stick relay is controlled by a track relay and a slow-actingcircuit controller governed by a signal or line relay. When semaphoresignals are used, as shown the directiona 1927. Serial No. 191,735;

in my prior patent, the usual circuit controller operated by thesemaphore signal mechanism" has the necessary operating characteristicsof the slow-actin circuit controller governing Istick relay; but whencolor light signals are used, special provisions must be made to obtainsuch a slow-acting circuit controller. As shown in my prior application,Ser. No. 120,432 filed July 3, 1926, a slow releasing relay, governed bythe line relay, may be employed to control the directional stick relay.Such a slow-releasing relay, however, while it can be readily designedto provide the required dela in the dropping of its armature upon itse-energization is relatively quick acting upon energization.

In View of the foregoing and other important considerations itis'proposed in accordance with the present invention to provide specialmeans to delay the energization of such a slow-releasing rela inresponse to energization of the home re ay of a signal location of anabsolute-permissive-block signal system, so that the momentaryenergization of such home relays will not cause the directional stickrelay associated therewith to be picked up.

An electro-thermalresponsive relay has slow acting characteristics whichmakes it suitable for controlling contacts an interval of time after acertain circuit is closed, but such thermal responsive relay or deviceis rather ineflicient and therefore it is not very suitable for use-as aregular relay in a signaling system; and more especially it is thereforeproposed to use a thermal device for picking up another relay of thestick type and to cause such another relay to cut theenergizing currentoff of the electro-thermal-responsive device, so that the feature of atime element delay is taken advantage of and the device need only beenergized for a very short time sufficient to cause closure of itscontacts, that is, its efliciency is not important when used in thisWay,

Other objects, purposes and characteristic features of the presentinvention will in part bepointed out hereinafter, and in part be obviousfrom the drawings.

In describing the invention in detail, reference will be made to theaccompanying drawings, in which Fig. 1 shows conventionally theapparatus at a signal location of an absolute-permissive-block signalsystem employing my invention; and

Fig. 2 conventionally illustrates similar apparatus employing a modifiedform of my invention.

Structure F z'g. 1.-In order to simplify the description of the presentinvention only the control circuits and apparatus of a single signallocation of an absolute-permissiveblock signal system has been sli'dwn.Referring to Fig. l of the drawings, there are shown three conditionstop-andstay light signals 1 and 2 at the end of a passing siding,containing a track switch S1, of which the signal 2 is a starting signaland the signal 1 a leaving signal for a signal track section. Twointermediate permissive three condition light signals 3 and 4 also havebeen shown. The stop-and-stay signals 1 and 2 are distinguishable fromthe permissive signals 3 and 4 by having the marker light M directly inline with the green, yellow and red lights, G, Y and B respectively ofthe light signal units thereof; whereas the marker light M of thepermissive signals 3 and 4 is set off to the right or to the left of thesignals G. Y and R thereof. Of the single track section shown, the blockbetween the signals 1 and 3 is di- Vided into two sections. but may. ifdesired, have more or less than two sections, depending on localconditions, each section of which is provided with the usual closedtrack circuit including a battery B and a suitable track relay. Thetrack relays for these cut sections have been conventionally shown bydotted lines and are designated QT and ST, respectively.

The control relays and circuits for the sig nal 3 only have been shown,of which the home relay 3H is directly controlled by the track relays QTand 3T through a circuit as follows :beginning at a terminal I3 (-lorwhich is plus if the signal 1 is clear or caution and is minus when thesignal 1 is at stop, front contact 11 of the track relay 2T, wire 12-,front contact 13 of the track relay 3T, wire 14:, winding of the homerelay 3H, to the common return wire 0 connected to the midpoint of saidbattery. This home relay 3H through its front contact 15 may applycurrent to the winding of the thermal relay Til if the pole changerrelay 31 C is to be energized. Normally this home relay 3H through itsfront contact 15 maintains the pole changer relay 31 C energized throughthe following stick circuit :-beginning at the terminal B+, frontcontact 15 of the home relay 3H, wire 16, winding of the pole changer3PC, wires 17 and 18, front stick contact 19 of the pole changer relay31 C, to the terminal 13-. The home relay 3H is a polar neutral relay ofthe usual construction, and this home relay in conjunction with the slowdropping pole changer relay 3P0 controls the indicating condition-of thelight signal-3 through circuits which have been shown by dotted linesand are well understood by those skilled in this art. The signalapparatus in question also includes the usual directional stick relay 3Sthe function of which is understood by those skilled in the art ofsingle track railway signaling.

Operation Fig. 1.In order to get a clear understanding of the advance inthe art contributed by the present invention, it is '-be lievedexpedient to first consider the movement of a train from right to leftby the signal 3 in which case the relays 3H, Z-BPC-and.

3S, change from their normal to their abnormal condition, and in whichcase the function of the slow acting electro-thermal-responsive relaydoes not come into play except as to its regularfunction of picking upthe pole changer relay, and thereafter consider the movement of a shorttrain, such as an engine and tender running alone moving from left toright, in which case the functioning of the thermal relay comes intoplay and in connection with which train movement the weakness of asystem not employing a means for de laying the closure of certaincontacts of the pole changer relay 3P6 may be more definitely pointedout. It may be pointed out at this time that the function of the stickrelay 38 in an absolutc-permissive-block sys tem is to shunt the frontcontact 20 of the relay SPC, which contact is contained in the linecircuit 21 of the home relay for the next signal in the rear, so thatsaid home relay in the rear may be energized in spite of deenclgizationof the pole changer relay SPC the signal in question, provided the trainwhich passed was moving from right to left and picked up this stickrelay, all of which is well known by those skilled in the art of A. P.B. signaling.

Let us now consider the movement of a train from right to left by signal3. As soon as this train passes the signal 3 the track relay 3T isde-energized which in turn de-energizes the home relay 3H.De-energization of the home relay 3H opens contact 15, and therebycauses de-energization of the pole changer relay 3PC. Since, however,the pole changer relay 31 C which, when direct current is used, in mostinstances comprises a relay having a ferrule or bucking coil thereonopposing a sudden change of flux in the relay magnetic structure, isslow in dropping, and for this reason keeps its contact 24 closed forsome time after de-energization of its cuit causes the stick relay 3S topick up and as soon as picked up is stuck up through the.

following circuit:-beginning at the terminal B+ front stick contact 30of relay 3S,

wires 31 and 32, back contact 33 of the home relay 3H, wires34 and 26,winding of the relay 3S, wire 27 to the terminal B. After a shortinterval of delay there .is another stick circuit completed which is thesame as the one just traced except that for the back contact 33 of thehome relay 3H is substituted the back'contact 35 of the relay 3P0 andWires 36 and 25, so that the stick relay 3S is stuck up so long aseither the home relay 3H or the pole changer relay SPC are de-energized.This energization of the stick relay 3S permits another train to followthe-train in question with signal protection the same as is afforded indouble tracksignaling, all without permitting an opposing train to enterthe single track section in question, as well understood by thoseskilled in the art.

If this train continues its movement from right to left, assuming it tobe a train of average length, the home relay 3H will remaindeeenergizeduntil the train has completely passed the signal 1. If thistrain just considered, however, is a very short train, such as an engineand tender running alone, and it moves at a rather high speed, it wouldbe possible for the contact 13 to close due to the clearance of thefirst track section before the contact 11 ofthe second track sectionisopencd, so that the home relay 3H is momentarily energized. If thearrangement were such that the home relay 3H directly controlled thepole changer relay 31 C, as is the case in my prior application, itwould have been possible for the relay 3H and 3PC to momentarily pick upand thereby cause dropping of the stick relay 3S. This would notestablish a dangerous condition, because all it would do'is reventanother train following the train in question, which of course would beentirel safe, but would not facilitate proper tra c movement.

Let us. now see what, transpires when the train in question moving fromright to left passes entirely off of the track circuit containing trackrelay 2T. 'This'causes the con tact 11 of this track relay 2T to closeand complete an energizing circuit for the home relay 3H. When the homerelay 3H picks up the opening of its back contact 33 will open one stickcircuit for the stick relay 38, but the other stick circuit thereof isstill intact and therefore the stick relay 38 remains energized. Theclosure of the contact 15 of the home relay 3H, however, completes anenergizing circuit for the thermal relay TR which may be traced asfollows :be-

ginning at the terminal B+ front contact 15 of the home relay 3H, wire40, winding of the thermal relay TR, wire 41, back contact 19 of therelay 3PC to the terminal B. With the thermal relay TR energized theleaf, or prong, 42 constructed of thermal metal, will after a time closethe contacts 4243 and complete a pick up circuit for the relay 3P0,which circuit may be traced as follows :beginning at the terminal -B+,front contact 15 of relay 3H, wire 16, winding of the relay 3PC, wires17 and 44, contacts 4243 of the thermal relay TR, to the terminal B. Itmay be pointed out here that the relay TR may constitute any suitableform of slow acting device and if a thermal responsive device is used,it preferably is made of two metals having different temof expansionwelded toperature .co-efiicients gether.

The completion of this circuit causes the relay 3P0 to assume itsenergized condition, upon which the stick circuit therefore heretoforetraced is completed. As soon as the pole changer relay 31 C is energizedthe energizing circuit for the thermal relay TR just traced, is brokenat the contact 19 of the relay 3P0. It is thus noted that the relay TRmay be a rather ineflicient large energ consuming device, because it isenergized or a short time only. As soon as the relay 31 C assumes itsenergized condition, the other stick circuit for the relay 38 is brokenat the contact 35, and the stick relay 3S assumes its de -ener- ,ceiveenergization through the contact 20 of the relay 3P0.

Let us "now assume that an engine and .tender unit is running alone, andmoving from left to right between the signals 1 and 3, under whichcondition the relays 3H and 31 C are de-energized and in turn all thehome and pole changer relays for the signals covering west bound trafficare held at danger by reason of the usual tumble down circuit, becauseno west bound trains should enter the single track section in-questionso long as there is an east bound train moving therein. Upon the passageof the short train in question from the tracksection containing trackrelay 2T upon the track section containing the track relay 3T, thecontact 11 will be immediately closed due to the quick picking up of thetrack relay 2T and possibly will be closed before the contact 13 oftrack relay 3T is opened, because the track relay 3T is slow to drop,its winding being shunted by the train thus causing it to act like ashorting slug, and therefore the home relay 3H is momentarily energized.In accordance with the present invention, due to the delay imposed bythe thermal relay, the 'pole changer relay 3P0 cannot pick up for an,appreciable time, so that the pick up circuit,

for the stick relay 3S will not be completed even though it is closed atcontact 22 of the track relay 3T, because this pick up circuit is openat the contact 24 of the relay 3P0. If, on the other hand, the homerelay 3H directly controlled the ole changer relay 3P0, it might bepossible or the pole changer relay 31 C to pick up and close its contact24 in which event the stick relay 3S would have been picked up.

The picking up of the stick relay 3S b(y an east-bound train, whiclristhus avoide by my invention is objectionable, because it permits theclearing of. the next opposing signal, and under certain conditions oftrain movement, the necessary signaling protection for opposingtrains isnot provided.

The present invention, which generally speaking resides in the provisionof electroresponsive slow acting means for controlling the picking up ofa stick relay, has for convenience been shown applied to a specific formof absolute-permissive-block signaling system only. This application ofthe invention is not to be construed as a limitationot its field of usenor of the scope of the inven tion, since it is recognized that it maybe applied to any system where a stick relay is to be picked'up only inthe event a certain contact has been closed for an appreciable time, oranywhere where a device is to be operated a predetermined and anappreciable period of time after a control contact therefore closes andWhere the means for obtaining such delay consumesso much energy that itis expedient to employ applicants energy saving arrangement tosubstitute an eflicient stick relay for the ineflicient slow actingdevice after this slow acting device has carried out-its function ofdelaying such operation. In some cases it may be expedient to connect aplurality of slow-acting thermal devices, such as the device TR of Fig.1, so as to act sequentially so as to provide a greater time interval.uch an arrangement is shown in the modification of Fig. 2. In thismodification, the circuits controlling the relay 3S, are the same shownin Fig. 1 and need not be described. The pole-changer relay 3P0 isnormally maintained energized by a stick circuit including its frontcontact 19*, wires 16, 17, and 18, and a front contact 15 of the homerelay 3H the same as in Fig. 1. After the relay SPC has beende-energ'ized by opening of its stick circuit, thereby closing its backcontact 19", when the home relay 3H is again energized, a circuit forthe heating coil of the thermal element TR is established and may betraced from B through the back contact 19, wire 50, front contact 15 ofrelay 3H3 wires 51 and 52 through the heating coil to C. When thethermal device TR closes its contact 43, current is supplied to theheating coil of the thermal device TR", which in turn, after an intervalof time, closes its contact 43", supplying current to the heating coilof the thermal device TR. The closing of the contact 43 of the lastthermal device TR establishes a pick-up circuit for the relay 3PC,thereby energizing this relay for the same purpose, and with theresultant pperations explained in the modification of Having thus shownand described different specific embodiments of the invention, thishaving been done for the purpose of facilitating the description of the'nature of the invention and the manner in which it may be applied toexisting or other railway systems, it is desired to have it understoodthat the devices and apparatus illustrated have not been illustrated forthe purpose of showing the scope of the invention nor the exactapparatus preferably employed in practicing the invention and thatvarious changes, additions and modifications may be made to adapt theinvention to the particular problems encountered in practicing the same,all without departing from the spirit and scope of the invention and theidea of means underlying the same, except as demanded by the scope ofthe following claims.

lVhat I claim as new is 1- 1. In combination, a relay of the stick typehaving a stick circuit including its own front contact closed only whenit assumes its energized condition and having a pickup circuit, and aslow acting electro-responsive device having contacts closed only aftersaid electro-responsive device has been energized for a predeterminedperiod of time, said pickup circuit including the contacts of saidelectro-responsive device, and the energizing circuit of saidelectro-responsive device including a back contact of said stick relay.

2. In combination, a relay of the stick type having a stick circuitincluding its own front contact closed onlywhen it assumes its energizedcondition and having a pick-up circuit, and a slow acting thermal devicehaving contacts closed only after it has been electrically energized fora predetermined period of time, said pick-up circuit including thecontacts of said thermal device, and the energizing circuit of saidthermal device including a back contact of 'said stick relay, andcontrol contacts in said stick circuit for controlling said stick relay.

3; In combination, a relay of the stick type having a stick circuitincluding its own front contact closed only when it assumes itsenergizcd condition and having a pick-up circuit, and a slow actingthermal device having contacts closed only after it has beenelectrically energized for a predetermined period of time, said pick-upcircuit including the contacts of said thermal device, and theenergizing circuit of said thermal device including a back contactofysaid stick relay,'and control contacts in both said pickup and stickcircuits of said stick relay and x in the energizing circuit for saidthermal p stick relay.

device for controlling energization of said 4. In a single track railwaysignaling. system of the absolute-permissive-block type; the combinationwith a signal and control apparatus therefore including a home relay, apole changer relay, a stick relay and a thermal device; a divided blockin advance of said signal containing a plurality of track sections eachhaving a track circuit including the usual track relay; a circuit forenergizing said home relay including in series the contacts of saidtrack relays; a stick circuit for said pole changer relay including afront contact of said home relay; a pick-up circuit for said polechanger relay including a contact of said thermal device and a frontcontact of-said home relay inseries, a pick-up circuit for said stickrelay including a front contact of said pole changer relay; and a stickcircuit for said stick relay including a back contact of said homerelay.

5. A single track railway signaling system of theabsolute-permissive-block type; the combination with a signal andcontrol apparatus therefore including a home relay, a pole changerrelay, a directional stick relay and a slow acting relay; a dividedblock in advance of said signal'containing a plurality of track sectionseach having a track circuit including the usual track relay; a circuitfor energizing said home relay including in series the contacts of saidtrack relays; a stick circuit for said pole changer relay -in cluding afront contact of said home relay; a pick-up, circuit for said polechanger relay including a contact of said slow acting relay and a frontcontact of said home relay in series, a pick-up circuit for said stickrelay including a front contact of said pole changer relay; and a stickcircuit for said stick relay including aback contact of said home relay.

6. In a single track railway signaling system of theabsolute-permisssive-block type, the combination with a directionalstick relay for permitting trains to follow each other through a singletrack section without permitting trainsvto move toward each other, aslow dropping relay for permitting said stick relay to pick-up whenthere is a train moving in a certain direction .by a control point, and

supplemental means for delaying the picking-up of said slow droppingrelay to prevent said directional stick relay picking up upon amomentary application of energy thereto.

7. In a single track railway signaling system of the absolute-permissiveblock type,

tion without permitting trains to move toward each other, a slowdropping stick relay for permitting said directional stick relay to'pick-up when there is a train moving in a certain, direction by acontrol point, and electro-thermal' responsive device for closing apick-up circuit for said slow dropping stlck relay only after aninterval of time has elapsed since said electro-thermal responsivedevice was electrically energized.

8. In a single track railway signaling system of theabsolute-permissive-block type, in combination with the usualdirectional stick relay provided for permitting trains to follow eachother through a single track section without permitting trains to movetoward each other, a slow dropping stick relay for permitting saiddirectional stick relay to pick-up when there is a train moving in acertain direction by a control point, an electro-thermal responsivedevice rendered active an interval of time after being energized forclosing a pick-up circuit for said slow droping stick relay and havingan energized circuit including a back contact of saidslow droppingrelay, and control contacts in the energizing circuits of said slowdropping relay and said electro-thernial responsive device.

9. A single track railway signaling system of theabsolute-permissive-block type, the combination with the usualdirectional stick relay provided for permitting trains to follow eachother through a single track section without permitting trains to movetoward each other, a slow dropping stick relay for permitting saiddirectional stick relay to pick-up when there is a train moving in acertain direction by a control point, an

. electro-thermal-respons1ve device for closing a pick-up circuit forsaid slow dro pingstic relay only after an interval 0 time has.

clasped after said electro-thermal responsive device is electricallyenergized, and means .for de-energizing said electro-thermal relay; apole changer relay for controlling the signal lamps of the light signalof said system and the home relay of the next signal in the rear, meansfor-rendering said pole changer relay slow to dro to permit picking upof the directional stic re ay and avoiding flashing of the danger lampof said signal lamps, and other means for delaying the picking up ofsaid pole changer relay.

11. In a single track railway system of the absolute-permissive blocklight signal type;

.' pole changer relay'governed by said home relay forcontrolling thesignal lampsof a particular light signal of said system and the homerelay of the next signal in the rear of said light signal and having anormally opened and normally closed contact; a pickup circuit for saiddirectional stick relay including said normally closed contact; astickcircuit for said directional stick relay including said normally openedcontact; and means for delaying the energization of said pole.- changerrelay after de-energization thereof for a time interval following theenergization of said home relay.

12. In an absolute permissive block signaling system, the combinationwith the usual home relay associated with an intermediate signal of asingle track section of such system, a track relay for each of twosuccessive track circuits adjacent said intermediate signal, a slowdropping relay, a slow acting thermal relay controlled by said homerelay for picking up said slow dropping relay, and a directional stickrelay having a pick-up circuit including a front contact of saidslow-dropping relay and a stick circuit including a back contact of saidslow-drop ping relay.

13. In an absolute-permissive-block signaling system, the combinationwith an intermediate signal, two track sections in advance of saidsignal each having a track relay, a home relay controlling theindications of said signal and de-energized if either of said tracksections is occupled, a slow-releasing relay, a thermal relay controlledby said home relay for closing a pick-up circuit for said slow-releasingrelay, a directional stick relay, a pick-up circuit for said directionalstick relay including a front contact of said slow-releasing relay and aback contact of the track relay of the track section next in advance ofsaid signal, and a stick circuit for said directional stick relayincluding a back contact of said home relay and a back contact of saidslow-releasing relay in multiple.

14. In a signaling system of the type described, a normally inactivethermal device having normally open contacts, a slow-releasingpolechanger stick relay having a pick-up circuit including said normallyopen contacts, an energizing circuit for said thermaldevice including aback contact of said pole-changer relay, and a directional stick relayhaving a pick-up circuit, including a front contact of said pole-changerrelay.

15. In combination, a relay of the stick type, having a stick contact, acontrol relay. :1 slow acting relay closing a contact only after apredetermined time of energization thereof, an energizing circuit Iorsaid slow acting relay including a back contact of said stick relay anda front contact of said control relay, a pick-up circuit for said stickrelay including the contact of said slow acting relay, and a stickcircuit for said stick rel'ay including a front contact of said controlrelay and the stick contact of said stick relay, whereby the picking upof the stick relay is delayed by said predetermined period of time, saidslow acting relay is (lo-energized upon energization of said stick relayand said stick relay if once picked up is held energized so long as saidcontrol relay is energized.

16. In an absolutepermissive-block signaling system, in combination witha directional stick relay having a pick-up circuit, a slowdropping relayhaving a front contact included in said pick-up circuit, a home relaycontrolling said slow-dropping relay, and other means governed by saidhome relay for delaying the energization of said slow-dropping relayafter de-energization thereof by said home relay for a time intervalfollowing the re-energization of said home relay, whereby the closing ofsaid front contact in the pick-up circuit for said directional stickrelay, after the opening thereof, is delayed by the action of said othermeans.

17 In a single track railway signal system of theabsolutepermissive-block light signal type; the combination with theusual home relay, track relays controlling said home relay and adirectional stick relay; a slow-releasing pole changer relay forcontrolling the signal lamps of a particular light signal of said systemand the home relay of the next signal in the rear of said light signaland having a normally open and a normally closed contact; a pick-upcircuit for said directional stick relay including said normally closedcontact; a stick circuit for said directional stick relay including saidnormally open contact; and electrically operable time-responsive meansrendered effective only upon deenergization of said pole-changer relayand energization of said home relay for delaying the r-energization ofsaid pole-changer relay for a limited interval of time.

18. In a railway signaling system, a plurality of track relays, a linerelay controlled by said track relays, a repeater relay governed by saidline relay, and electrically operable means for delaying theenergization of said repeater relay when once de-ener'gized for a timeinterval following the re-energization of said line relay.

19. In a railway signaling system, aplurality of track relays, a linerelay controlled by said track relays, a slow-releasing signal relayhaving an energizing circuit including a front contact of said linerelay, a directional relay responsive to the direction of y electricallyoperable means for delaying the energization of said signal relay afterdeenergization thereof fora time interval subsequent to there-energization of the line relay.

20. In a railway signaling system, a line relay controlled by aplurality of track circuits, a slow-releasing signal relay governed bysaid line relay, a color light signal, control circuits for said signalgoverned by said line relay and said signal relay, and electricallyoperable time responsive means for delaying the energization of saidsignal relay after de-energization thereof for a time intervalsubsequent to the energization of a line relay.

9.1. In a railway signaling system, a line relay governed by a pluralityof track circuits, a repeater relay, a stick circuit for said repeaterrelay including a front contact of the line relay, and electricallyoperable means set into operation upon d-e-energization of the repeaterrelay and energization of the line relay for picking up said repeaterrelay after a time interval of delay.

22. In a railway signaling'systeni, a line relay, a slow-releasingrepeating relay governed by said line relay, a directional relaycontrolled by said repeater relay, and a thermal time element device fordelaying the energization of said repeater relay after eachde-energization thereof for a time interval subsequent to theenergization of said line relay.

23. In a railway signaling system, a line relay controlled by aplurality of track circuits, a slow-releasing repeater relay, a stickcircuit for the repeater relay opened upon de-energization of the linerelay. a pick-up circuit for said repeater relay. and a thermal timeelement device controlled by a back contact of said repeater relay and afront contact ofsaid line relay for establishing said pickup circuitafter an interval of delay, and

signaling means controlled by said repeater relay.

24. In a signaling system for single track railroads, a line relaygoverned by a plurality of track circuits, a slow-releasing repeaterrelay, a stick circuit for the repeater relay opened uponde-energization of said line relay, a directional relay governed by oneof said track relays and by said repeater re lay. and a thermal elementcontrolled by a hack contact of said repeater relay and a front contactof said line relay for delaying the energizati-on of said repcaterrelayafter interruption of its stick circuit for a time interval followingre-energization 0f the line relay.

25. In a system of signaling for single track railroads, a line relay, arepeater relay governed by said line relay, a directional relay having aholding circuit including a. back contact of said repeater relay, andtime- SEDGWICK N. WIGHT.

